People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

Pot Documentary, 'Mile High: The Comeback Of Cannabis,' Will Pass Out Free Marijuana To People At Colorado Screening

Stand-up comedian and filmmaker of the new documentary, "Mile High: The Comeback Of Cannabis," Adam Hartle, plans to hand out free weed to people who attend the screening. Photo courtesy of Shutterstock

In Colorado, a filmmaker seems to have figured out a new and fairly obvious marketing plan — handing out free weed to whoever shows up to his new documentary’s screening.

“I’ll be standing outside the Mayan and Boulder theaters before each screening this week, handing out a small amount of legal marijuana to anyone over 21 with a valid ID to take home to enjoy responsibly,” Adam Hartle, the film’s producer, told Deadline. “No purchase necessary, but we highly encourage you to stay and watch the film.”

The film, “Mile High: The Comeback of Cannabis,” documents the story behind Colorado’s Amendment 64, which officially made growing, selling, and smoking weed legal in Colorado. With both man-on-the-street and physician interviews, Hartle aims to clear up any preconceived suspicions about recreational marijuana, as well as hear the opinions of regular Coloradans. As a stand-up comedian, he coined the film as the “world’s first historical comedy documentary.”

In 2012, Colorado became the first place, anywhere in the world, to make marijuana legal for anyone over the age of 21. Not even Amsterdam has pot sales that are as legal as they are in Colorado. Though the use of marijuana was technically legal earlier in the state in 2012, specially licensed stores opened up on Jan. 1, 2014. Marijuana use, possession, and sales are still illegal under federal law, however. Recently, New York became the 23rd state to legalize medical marijuana, but no other state other than Colorado allows recreational marijuana. Thus, the legalization debate continues throughout the rest of the country.

“We’ve shown this film to a few test audiences so far, and what we’ve found is the 20- to 40-year-old demographic who have used cannabis before absolutely love it, and the older crowd who hasn’t find it less favorable,” the documentary’s co-writer Anthony Hashem told Deadline.